The invention concerns additional novel elements and circuits for use with the devices disclosed in our U.S. Pat. No. 3,749,921, issued July 31st, 1973. That patent discloses various devices for controlling the impulses generated by the discharge of a capacitor placed either in series or in parallel with a load and, in the case of a parallel connection, having no more than one electronic switch. That patent also discloses novel switching tubes for uses as such switch.
One drawback of such devices is that when a high contrast scene, or subject, is to be photographed, the reflected light will not be measured with sufficient accuracy. Moreover, when a reflected light measuring and duration control device is used in a camera, and the subject to be photographed is moved and/or the illumination intensity is fluctuating, accurate measurement of the light reflected to the camera with known light measuring devices becomes difficult, and sometimes even practically impossible, and in any case requires a number of complex measurements, computations and evaluations.